Yes, girls should wear short shorts. Personally, it is my thought that anything longer than the tip of the middle finger is too LONG for men or women, boys or girls. As long as there's not butt cheek hanging out, I have no problem with it.
There is a caveat. If you are not fit, but heavily obese, please, do not dress up in short shorts, they do not look good on you. I like my shorts four to five inches for outside, and casual short shorts for around the house and I'm a straight adult male, so there is nothing wrong with them. And, considering that, a few decades back, they were the norm for men and women, we ought go back to that sense of body freedom.

I don't see a problem with it at all, other than the fact u may get some unwelcome guys looking at u, if they are ridiculously short. Honestly just use common sense, and think what your reason is. Is it to look pretty or attract attention? Now some attention is okay, but some females wear shirts and bras which show half their boobs. That isn't using common sense. And honestly I believe a girl should be able to wear anything she likes without having to worry about getting raped. But here is the thing. If u are a girl who doesn't like getting stares from random guys or catcalls, use common sense. I'm not justifying the actions of guys, but u should know what guys are like. Don't invite trouble. So when it comes to wearing short shorts? Not a problem in my opinion. But if u show half your boobs you cannot complain about getting some stares.

Because they see their Idols acting like whores E.g Nikki Minaj, Rhianna ect, so they decide its the right thing to do.
No, girls, especially the young girls I see walking around in short shorts should NOT be aloud to wear them.